Conventionally, in straddle vehicles such as a motorcycle, various attempts have been made to ensure a layout space in which components incorporated into the vehicle, such as engine components and electric components, are placed. For example, in a motorcycle disclosed in Patent Literature 1, a component mounting member made of a resin is disposed such that it is surrounded by right and left main frames extending rearward from a head pipe and sandwiched between a fuel tank placed thereabove and an air-intake chamber placed therebelow, and a plurality of components are mounted to the component mounting member.
This component mounting member is provided integrally with mounting arms, engagement elements, guide elements, etc. Electric components such as an ignition coil, a CDI unit, a coupler, a switch, and a relay are easily mounted to the component mounting member, without using a tool. In front of the component mounting member, a regulator is mounted to the right and left main frames extending from the head pipe via brackets.
By the way, a current of a relatively great magnitude flows through the electric components in the electric power supply system, such as the regulator and the relay. Therefore, it is necessary to suppress a temperature increase in these components. In the case of the motorcycle, it is necessary to consider an influence of heat from the engine on these components. To this end, Patent Literature 2 discloses that the regulator is placed on an upper surface of an air cleaner in an air-intake system to block heat radiated from the engine placed therebelow, and heat radiation from the regulator is facilitated by air flowing through an interior of the air cleaner.
More specifically, in the motorcycle disclosed in Patent Literature 2, a fuel tank is disposed at a relatively rearward position and only in a rear half portion of a tank cover, the air cleaner is accommodated in front of the fuel tank, i.e., a front half portion of the tank cover, and the regulator is placed in a narrow space between the upper surface of the air cleaner and the tank cover covering the air cleaner from above. In addition, a control unit is disposed in this narrow space such that the control unit and the regulator are arranged side by side.